July 24, 2013

CDC Warns Of Rare Parasite Outbreak, 250 Infected Across US

Centers for Disease Control and Prevention (CDC) officials are warning about potentially tainted produce that may have caused sickness in over 250 people across several US states.

The produce, which would have been shipped across state lines, is believed to have been contaminated with a rare parasite known as cyclospora. Almost 120 people have reportedly tested positive for the rare protozoan in Iowa, an additional 65 tested positive in Texas and another 68 in Nebraska, according to state officials. Several other cases have been reported in Wisconsin, Illinois and Kansas, although the Illinois case may yet be traced back to Iowa.

Officials have yet to formally identify a source for the illnesses, which were reported from mid-June through July.

"Nothing has been implicated yet in a formal sense," Dr. Barbara Herwaldt, a medical epidemiologist with the CDC's division of parasitic diseases and malaria centers, told NBC News. "No food item has been identified as the source of the outbreak."

Some officials in affected states have indicated that fresh vegetables may be the source, based on patient interviews. Herwaldt said if tainted produce were shipped across state lines, it could account for the outbreak across several states. Multiple food sources or contaminated water could also be behind the rash of illnesses. CDC officials said they were not yet sure whether all of the reported cases are related.

Cyclospora are not known to thrive in the US - making the possibility that imported produce may be the culprit highly likely, Herwaldt said.

In 1996, imported Guatemalan raspberries were blamed for an outbreak that affected 1,500 people in North America. In 1997, similar raspberry-related outbreak affected more than 1,000 people, according to CDC records.

Confirmed cyclospora cases must be reported to the CDC in 39 states, plus New York City and Washington, D.C., Herwaldt said. The agency encourages officials in other states to report infections as well, for both treatment and containment reasons.

To prevent the spread of cyclospora and other pathogens, the CDC recommends that consumers wash and scrub fresh produce. Washing hands before handling produce and refrigeration also seem to slow the parasite's ability to infect, Herwaldt added.

She also said that contaminated produce could have already made its way though the food supply, but it was still too soon to tell.

"What we don't know yet is whether the transmission or spread of the parasite is ongoing."

Cyclospora are regularly found in subtropical or tropical countries and have been found in fresh imported produce in the past. The illness is typically spread by ingesting foods or water contaminated with feces. Symptoms of the infection include fatigue, loss of appetite, bloating, stomach cramps, vomiting, muscle aches and low-grade fever. A cyclospora infection is not typically considered life threatening.

The most effective known treatment for an infection is a seven-day regimen of the drug trimethoprim-sulfamethoxazole. The antibacterial drug has proved so effective that some doctors are debating its use as a preventative measure for individuals whose immune system has been compromised by HIV or other autoimmune diseases.